1. Field of the Invention
This invention relates to ball bearings mainly used for OA apparatus motors and components thereof.
2. Description of the Prior Art
A usual spindle motor used for OA apparatuses, as shown in FIG. 10, comprises a spindle, a hub as a rotor and a flange as a base, and the spindle is supported in a ball bearing which comprises an inner and an outer ring provided in a sleeve. These components are individually formed as separate members.
Since the prior art motor components are thus independent parts, the motor has a large number of components. Besides, it is necessary to assemble together these components, leading to a large number of steps involved in the motor manufacture and thus to a high cost of manufacture.
Further, in the prior art ball bearing structure, it is not easy to obtain the vibration accuracy of the spindle, and it is difficult to expect substantial improvement of the vibration accuracy.
Further, it has been not easy to obtain the vibration accuracy of the spindle for a pivot or a pulley as rotational component of OA apparatus.